Does Power Estimation Propagate Switching Activities?

[miho]

hello,

I am trying to do power estimation on a fairly complex design using Synopsys Power Compiler. So far I only set switching activities by hand. If I, e.g., set the switching activities for the inputs of a multiplier, will the power compiler estimate correct switching avtivities for all internal nets of the multiplier?

If yes, how complex can a design be so that such propagated switching activities are estimated correctly? Is there any rule of thumb?

Thanks

 

[linuxluo]

hi,
As I remember , switching activity is not propagated in power compiler. you have to set it.

 

[farmerwang]

You have to set the switch activity using the SAIF from simulation. Therefore, the pattern that you choose to run your simulation has a large impact on the result of the power analysis. You need to carefully choos a test case that can reflect your design's typical application. BTW, gate level simulation with full timing can give you the most acurate result, but very very very slow. And you need to use powermill to analysis the MEMORY power consumption.